Want free $5 credit for Amazon Instant Video, usable for movies and TV shows on Amazon Instant Video? All you need is an Amazon account, a Twitter account, and two spare minutes.

Before we proceed, take note that by participating in this offer your Twitter account will

Automatically follow @amazonvideo and @amazon_movies;

Automatically tweet a promotional message for Amazon;

Allow Amazon’s Twitter app access to your Twitter account.

If you prefer, after you take advantage of this offer, you can manually unfollow @amazonvideo and @amazon_movies, delete the promotional tweet, and revoke Amazon’s Twitter app’s access to your account.

That said, to get free $5 credit on Amazon Instant Video, follow these simple steps:

Login to your Amazon account. (Or, create an account if you don’t have one already.)

Once logged in, you should be redirected back to the promotion page (if you aren’t, click here[1]). At the promotion page click Tweet and Get $5:

[3]

A new window will popup asking you to login to your Twitter account (if you aren’t already logged in) and to give access to Amazon’s Twitter app:

[4]

After you have clicked on Authorize app, wait a few seconds while Twitter does its thing. Once finished, the popup window should close and the promotion page you had open should refresh and show a success message like the following:

[5]

If you see a message like the one shown in the above screenshot, congratulations! You now have a $5 Amazon Instant Video credit applied to your Amazon account. To use the credit, simply purchase a movie to TV show. As you make purchases, the balance will be taken from your $5 credit until the whole credit is used up. (Note: “The credit may not be used for certain titles. The detail pages for such titles will state that they are not eligible for promotions.“)

If you receive any sort of error and don’t see the message shown above, simply refresh the page and try again. I myself ran into an error the first time around but tried again and it worked perfectly.

Last but not the least, take note this promotion is available until September 2, 2011, at 11:59 PM PST. Take advantage it before that time! Also take note that if you don’t use the $5 credit, it will expire October 31, 2011, at 11:59 PM PST.